Currently TFT-LCD (Thin Film Transistor Liquid Crystal Display) products have been applied widely in people's productions and livings, including televisions, monitors and portable electronic display products etc. The image sticking of a display panel becomes one of main factors affecting the display picture quality of a product. The image sticking is a phenomenon occurring inside a liquid crystal cell. Due to displaying of a static picture for a long time, when changing into other images, the liquid crystal molecules can not be deflected in time and thoroughly to adapt to a new picture, so that the pattern of the original image still remains, thus affecting the display effect. In accordance with the difference in the shape and the location, the image sticking may be classified into two types, that is, the area image sticking and the line image sticking. The main reason of producing the image sticking is the influence of residual charges, which includes different distributions of polarization charges generated inside a liquid crystal cell in externally applied electric field and impurity charges inside the liquid crystal cell. These residual charges will affect the orientations of liquid crystals at the top and the bottom of the liquid crystal cell, so that the image sticking occurs in the whole panel area, and it is more severely distributed at the image junction position with obvious color difference. However, the electric field applied within a liquid crystal cell of an FFS (Fringe Field Switching) mode liquid crystal display panel is a horizontal electric field which is produced on the substrate on one side of a TFT such that the polarization charges and the impurity charges within the liquid crystal cell aggregate more easily in the electric field, that is, the phenomenon of the image sticking occurs more easily.
In the prior art, the image sticking is eliminated mainly by adjusting the voltage of a TFT-LCD product, that is, by testing a VT curve to determine the voltage of an intermediate gray scale (L127), and then by adjusting the voltage of a common electrode such that the flicker value of a display screen corresponding to the gray scale is the minimum, thereby fixing the voltage of the common electrode, and further adjusting other gamma voltage pairs so that the transmittances of respective gray scales are the same as that on the gamma standard curve.
However, the voltage adjustment method in the prior art considers only the matching between the transmittances of respective gray scales and the gamma standard curve, therefore, the voltages set by the method may be asymmetrical with respect to the voltage of the common electrode, thereby producing a direct current biased electric field, so that ions within the liquid crystal cell aggregate, which affects the liquid crystal deflection within the liquid crystal cell, resulting in that the phenomenon of the image sticking occurs on the display panel. For an FFS mode liquid crystal display panel, the image sticking produced by such a case is more severe.